iommu: Pass struct iommu_iotlb_gather to ->unmap() and ->iotlb_sync()

To allow IOMMU drivers to batch up TLB flushing operations and postpone
them until ->iotlb_sync() is called, extend the prototypes for the
->unmap() and ->iotlb_sync() IOMMU ops callbacks to take a pointer to
the current iommu_iotlb_gather structure.

All affected IOMMU drivers are updated, but there should be no
functional change since the extra parameter is ignored for now.

Signed-off-by: Will Deacon <will@kernel.org>

drivers/iommu/intel-iommu.c

@@ -5147,7 +5147,8 @@ static int intel_iommu_map(struct iommu_domain *domain,
 }
 
 static size_t intel_iommu_unmap(struct iommu_domain *domain,
-				unsigned long iova, size_t size)
+				unsigned long iova, size_t size,
+				struct iommu_iotlb_gather *gather)
 {
 	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
 	struct page *freelist = NULL;